Answer :

To determine the number of significant figures in the mass [tex]\( 3.80 \times 10^{-4} \)[/tex] kg, we need to analyze the digits present in the given value. Here is a step-by-step breakdown:

1. Identify the digits: In the expression [tex]\( 3.80 \times 10^{-4} \)[/tex], we are primarily concerned with the coefficient [tex]\( 3.80 \)[/tex].

2. Count the significant figures in [tex]\( 3.80 \)[/tex]:
- The digit '3' is a non-zero digit and thus significant.
- The digit '8' is also a non-zero digit and significant.
- The digit '0' follows after the decimal point and after non-zero digits, making it significant as well.

Combining this information, the coefficient [tex]\( 3.80 \)[/tex] has three significant figures.

Therefore, the mass [tex]\( 3.80 \times 10^{-4} \)[/tex] kg has three significant figures.